A few flights to New York were delayed an hour or more on Sunday at Hartsfield-Jackson Atlanta International Airport - the first day of air traffic controller furloughs – but federal officials warn the real test could come Monday when traffic is typically heavier, reports Atlanta Business Chronicle broadcast partner WXIA-TV.

Federal transportation officials have said Atlanta’s airport could feel the brunt of delays - up to three and a half hours in some cases - but that the average would be 11 minutes.

Passengers at Atlanta’s airport on Sunday said they were concerned about possible delays due to furloughs. Click here to view WXIA’s interviews with passengers.

Transportation Secretary Ray LaHood and Federal Aviation Administrator Michael Huerta said Thursday that without the furloughs they could find no way to cut $637 million from the agency’s budget as required by Congress, The Associated Press reported.

A spokeswoman for airline industry trade association group Airlines for America said the furloughs are unwarranted and that airlines are considering suing the government, the news service adds.

Officials have warned there could also be significant delays in Chicago, Los Angeles and New York.

Click here to access the Federal Aviation Administration website for flight delay information across the country.